Products From Crude Oil

Question 1

What are alkenes

Answer 1

Another family of hydrocarbons that contain a carbon carbon double bond

Question 2

What do double bond involve

Answer 2

Sharing two pairs of electrons

Question 3

What does unsaturated mean

Answer 3

Contains at least one double bond

Question 4

What is the general formula for alkenes

Answer 4

C(n)H(2n)

Question 5

Why is there not a methene

Answer 5

There is only one carbon atom is methane. There needs to be a carbon carbon double bond for for there to be an alkene

Question 6

How many bonds does carbon need to make to get a full outer shell

Answer 6

4

Question 7

What can alkenes also undergo just like alkanes

Answer 7

Combustion

Question 8

What is cracking

Answer 8

A process which breaks down large hydrocarbon molecules into smaller, more useful molecules

Question 9

Why do we need to crack

Answer 9

Some of the heavier fractions from fractional distillation are not useful as they are made of large molecules and are poor fuels

The smaller hydrocarbons are more useful

Unfortunately there is a high supply and low demand for large hydrocarbons and a low supply and a high demand for small hydrocarbons

Question 10

How does cracking work

Answer 10

It involves heating the hydrocarbon strongly so it turns into a gas and passes through a hot catalyst

Question 11

What type of reaction is cracking and what does it mean

Answer 11

Thermal decomposition reaction - breaking down a substance using heat

Question 12

What are the two types of products from cracking

Answer 12

Smaller alkane that is a more useful fuel

Alkenes

Question 13

What is the test for alkenes and result and explanation

Answer 13

Bromine water (orange)

Alkene present - turns colourless
Alkane present - stays orange

Explanation - alkenes have double bond so reacts as the double bond breaks

Question 14

Monomer definition

Answer 14

A small molecule that can combine wth similar molecules to form a long molecule called a polymer

Question 15

Polymer definition

Answer 15

Very long molecules made of smaller molecules called monomer

Question 16

What is addition polymerisation

Answer 16

The process where monomers join together by single bonds to form 1 large polymer molecule

Question 17

What is an example of a monomer

Answer 17

Alkenes

Question 18

What happens during addition polymerisation

Answer 18

Under high pressures and temperatures double bonds in the monomer molecules break to form a single bond

Millions of monomers join together by single bonds to form one long polymer

Question 19

What is the use of polyethene and what is the displayed formula

Answer 19

Plastic bags, milk cartons, shampoo bottles

n C=C

[—–C-C—– ] n

Question 20

What is the use of polypropene

Answer 20

Rope, milk crates

Question 21

Why does polystyrene and polypropene have different properties

Answer 21

They are made from different polymers and before that monomer so have different properties

Question 22

What are the two types of polyethene

Answer 22

Low density and high density

Question 23

How is low density polyethene made

Answer 23

Under high pressures and a trace of oxygen

Question 24

Why is low density polyethene low density

Answer 24

The polymer chains have random branches so are unable to patch closely together

Question 25

How is high density polyethene formed

Answer 25

Using a catalyst at 50degreesC, slightly high pressure

Question 26

Why is high density polyethene high density

Answer 26

The polymer chains are straighter and without branches so are able to pack closely together

Question 27

Why do plastics soften easily when heated

Answer 27

There are weak intermolecular forces between the molecules as there are no covalent bonds (cross links) so the plastic can soften easily when heated

Question 28

How can we classify polymers

Answer 28

By looking at what happens when they get heated

Question 29

What are thermosoftening polymers

Answer 29

Polymers which soften easily when heated and reset when cooled. They are made of polymer chains that are tangled together and can easily separate as they have weak intermolecular forces between them

Question 30

What are thermosetting polymers

Answer 30

Polymers that do not melt when heated a they have strong covalent bonds between. The polymer chains called cross links

Question 31

Properties of thermosetting polymers (2)

Answer 31

Cross links don't break when heated Rigid

Question 32

Properties of thermosoftening polymers

Answer 32

Weak intermolecular forces that break when heated Melts easily but rehardened again when cooled so can be remoulded

Question 33

Why are plastic bags made out of thermosoftening polymers (2)

Answer 33

Flexible Tensile strength (can stretch)

Question 34

Why are thermosetting polymers used for pan handles

Answer 34

Don't melt under intense heat during cooking Rigid

Question 35

Why are waste plastics a problem

Answer 35

They take up space in landfill sites and take a long time to break down. Wildlife might also get trapped in the waste plastic and die

Question 36

What are biodegradable polymers

Answer 36

These plastics rot away in soil and are broken down by microorganisms

Question 37

What raw material is good to make biodegradable stuff

Answer 37

Plant

Question 38

What is the monomer of polylacticacid

Answer 38

Lactic acid

Question 39

How can non-biodegradable polymers be made to decompose more quickly

Answer 39

Use fermented cornstarch to make plastic material

Question 40

What are the problems with using cornstarch to make polymers (2)

Answer 40

Crops for food are being used for plastics (famine + increases food prices) Destruction of habitats

Question 41

What is the problem with using degradable polymers that break down in light

Answer 41

Most of the plastics won't decompose as they are buried in the landfill site

Question 42

What does corn starch speed up decomposition

Answer 42

Microorganisms feed on the corn starch in the plastic

Question 43

What are the two processes for making ethanol

Answer 43

Fermentation of sugar | Hydration of ethene

Question 44

Advantages of using the method fermentation of sugar to produce ethanol (3)

Answer 44

Uses renewable plant material Carbon neutral Cheap conditions- anaerobic respiration in yeast and warm temperatures

Question 45

Advantages of using the method of hydration of ethene to produce ethanol (4)

Answer 45

Continuous process Fast reaction 100% pure product first time High yield

Question 46

Disadvantages for using fermentation of sugar for producing ethanol (5)

Answer 46

``` Slow reaction Batch process Not 100% pure product first time Low yield Uses land to grow sugar cane (famine + increase food prices) ```

Question 47

Disadvantages for using hydration of ethene for producing ethanol (3)

Answer 47

Uses finite fossil fuels Not carbon neutral High temperatures and pressures

Question 48

How is the chemical structure of an alkene different to an alkane

Answer 48

Alkenes have double bonds

Question 49

What needs to reacts with ethene to produce ethanol

Answer 49

Steam

Question 50

Two differences between cracking and polymerisation

Answer 50

Long chains turn to short chains in cracking and short monomers join to make a long polymer Cracking had more than one product whereas polymerisation has one

Question 51

Why is cracking an important process in the oil industry

Answer 51

The supply for shorter hydrocarbon chains is low but the demand is high. The supply for longer hydrocarbon chains is high but the demand is low. Cracking will satisfy the demand

Question 52

What is the process called that separates a mixture with different boiling points

Answer 52

Fractional distillation

Question 53

Why is it important to keep control variables constant

Answer 53

So that only the independent variable ins allowed to have an affect on the dependent variable